Building work in Brentham began following the cutting of the first sod on 20 April 1901, with General Builders contracting to build the first nine houses (Vivian Terrace, now 71-87 Woodfield Road). More terraced villas followed in Woodfield Avenue, Woodfield Crescent and Brunner Road between 1901 and 1906.

In October 1905 Ealing Tenants completed the purchase of additional land from the Fowler's Hill estate, and in January 1907 a further thirty acres was acquired from the Pitshanger estate. With this expansion it was felt necessary to pay greater attention to the design of the houses and to the overall street plan. With this in mind, Raymond Unwin, consulting architect to Co-partnership Tenants Housing Council (a body formed to encourage co-partnership) and his partner, Barry Parker, were asked to design the layout of roads for the creation of the estate at Brentham.

From 1907, when 108 houses were completed, progress was rapid, with the construction of Ludlow Road (l907-9), Neville Road and Ruskin Gardens (both 1908-09) , upper Brentham Way (1909-19) and Meadvale Road (1908-13), Denison Road (1911) Holyoake Walk (1911-12), North View (1912), lower Brentham Way (1911-13) and Fowlers Walk (1914-15). Holyoake House containing 24 small flats for single and elderly people was built in 1912. 1914 saw 34 houses completed; apart from two houses in Brentham Way, all were in Fowlers Walk. By the end of the following year, a further 47 had been built in Fowlers Walk. By this time the estate was all but complete. Only the north and south ends of Brentham Way and the north part of Fowlers Walk remained to be developed, and Brentham was a flourishing community. By 1913, 510 houses had been built and the population stood at about 2,000. By the beginning of the First World War about 600 houses had been completed on the estate, which comprised some 60.5 acres.

Between 1903 and 1910 membership of Ealing Tenants Ltd rose from 59 to 353; share capital from £1,442 to £25,600, loan stock from £2,366 to £35,700; and value of property from £10,237 to £158,000. Dividends were limited to 5 per cent on share capital and 4-4.5 per cent on loan stock. Rents ranged from 6s. 6d. to 21s. per week, exclusive; it being a principle of the co-partnership philosophy that payment of rates and taxes by tenants would encourage a sense of civic responsibility. All dwellings were equipped with baths, though not all had bathrooms; in the flats the bath was placed in the kitchen. It was stipulated that gardens must be divided only by hedges. An area of five acres was reserved for allotments, and twelve acres for playing fields.

During the period Brentham was being built, co-partnership housing had become a national movement. The Co-partnership Tenants Housing Council had been set up in 1905 to advise numerous other societies, and a federation of tenants' societies had been established, known as Co-partnership Tenants Ltd, under the chairmanship of Henry Vivian. His advice on co-partnership housing schemes was eagerly sought, with the result that many of the later co-partnership schemes closely followed the ideas of Ealing Tenants and the Brentham estate. At Letchworth, Garden City Tenants Ltd had close associations with Brentham, and at Hampstead Vivian organised a tenants' society on the same lines as Ealing Tenants. The movement also spread overseas to many countries, including Germany, Canada and Russia. Vivian remained chairman of Ealing Tenants until 1911, when he resigned in favour of the vice-chairman, William Hutchings. His achievement was summed up by the journal Co-partnership (January 1912) in the following comment: ‘In the whole history of Industrial & Provident Societies during the last sixty years there is probably no instance of greater results from such small resources than in the case of Ealing Tenants Ltd. whose leadership Mr. Vivian has now relinquished.’